JP 2013-173438A discloses a leveling valve that adjusts the height of an air spring used in a railway vehicle. The leveling valve maintains a vehicle body at a certain height by selectively connecting the air spring to a compressor or an air discharge passage, depending on the rotational direction of a lever that rotates in accordance with a relative displacement of the vehicle body with respect to a truck.
The leveling valve includes an air supply valve that switches communication between the air spring and the compressor, an air discharge valve that switches communication between the air spring and the air discharge passage, and an actuator arm to which rotation of the lever is transmitted via a buffer spring.
Each of the air supply valve and the air discharge valve includes a cylindrical sleeve and a valve body that is arranged slidably inside the sleeve. The valve body of the air supply valve is pushed in a valve-closing direction by air pressure of the compressor, whereas the valve body of the air discharge valve is pushed in a valve-closing direction by air pressure of the air spring. The actuator arm rotates due to a restoring force of the buffer spring that deforms in accordance with rotation of the lever, and presses the valve body of the air supply valve or the air discharge valve. In this way, the air supply valve or the air discharge valve is opened.